1. Field of the Invention
The invention relates to the remote reading of utility meters which are located outside of a building in an underground enclosure.
2. Description of the Background Art
In moderate climate zones, utility meters are located in subsurface enclosures in areas adjacent to residences or other dwellings. Such enclosures are referred to as "pits." An example of such enclosure is illustrated in Haase et al., U.S. Pat. No. 1,781,280.
In Edwards et al., EPO Publication No. 0 252 184, meter data is transmitted from a utility meter in an underground pit to an electronic collection unit carried by a meter reading person. Scuilli, U.S. Pat. No. 4,758,836, shows an electronic metering unit which uses the inductive coupling method of the metering unit of Edwards et al.
More specifically, the electronic metering unit in Edwards et al. is electrically connected through a cable to a first inductive coil, which is positioned in an assembly that attaches to the pit lid. A second coil is located in the tip of a wand carried by a meter reading person. The meter reading person positions the tip of the wand in an opening in the pit lid assembly. This permits the coupling of signals by which the meter data is transmitted from the electronic meter to the collection unit.
There are a number of limitations in the prior art. First, the inductive coupling system does not provide a completely remote system as the meter reading person must approach relatively close to the pit lid to obtain a reading. Second, underground equipment must be made weather-resistant to varying temperature and moisture conditions. This is particularly true of electronic equipment to be used in underground enclosures.
The assembly for the inductive coupling system discussed above was not sealed against the elements. There was one opening for communication with the pit to allow a connection of a connecting cable and a second opening at the top to allow coupling to the second inductive coil.
Radio frequency meter reading systems have been known, but such prior radio frequency systems have been limited in use to buildings and above ground installations because the components were not sufficiently weather-resistant for use in underground pit enclosures.
Another limitation is that pit enclosures, being typically made of metal, present possible interference with radio transmission and reception.
The present invention is intended to overcome the limitations of the prior art.